Indonesia, the world's most populous Muslim nation, has strict laws against drug trafficking.

The head of Bali's Customs and Excise Agency monitoring division, Made Wijaya, warned at the time of her arrest that Sandiford could face execution if convicted.

"The main reason is because narcotics can massively endanger the young and, thus, whoever is caught with drugs should be severely punished. If three people can consume one gram of cocaine, then this operation has potentially saved up to 14,000 lives," he said.

The UK-based group Reprieve, which works to secure the human rights of prisoners around the world, said Sandiford was a vulnerable person who should not have been sentenced so harshly.

"Lindsay has always maintained that she only agreed to carry the package to Bali after receiving threats against the lives of her family," said Harriet McCulloch of Reprieve.

"She is clearly not a drug kingpin -- she has no money to pay for a lawyer, for the travel costs of defense witnesses or even for essentials like food and water.

"She has cooperated fully with the Indonesian authorities but has been sentenced to death while the gang operating in the UK, Thailand and Indonesia remain free to target other vulnerable people."

Any appeal for Sandiford must be filed within 14 days, McCulloch said in a written statement.

"It is vital that the British government do everything possible to support Lindsay's appeal against the death sentence," she added.

Sandiford's lawyer told Antara that it was likely that his client would appeal the sentence.

Reprieve says that after her arrest, Indonesian police interrogated Sandiford without a translator, legal representation or the assistance of the British Embassy for 10 days.

The U.S. State Department warns travelers to Indonesia of the risks of being caught smuggling drugs.

"Penalties for possession, use, or trafficking in illegal drugs in Indonesia are severe, and convicted offenders can expect long jail sentences and heavy fines," or the death penalty, it says. "Indonesian prisons are harsh and do not meet Western standards."